Natural Grocers marks 60th anniversary.

Natural Grocers said Wednesday it will officially celebrate its 60th anniversary the week of April 22 — which encompasses Earth Day — with a series of giveaways and special events.

The chain, founded in 1955 by Margaret and Philip Isely and based in Lakewood, Colo., operates 95 stores in 16 states, with sales estimated at $521 million for the fiscal year ended Sept. 30, 2014. The company said it expects to add 18 new stores this year.

“This anniversary celebrates our 60-year commitment to health, nutrition, empowerment and sustainability,” said Kemper Isely, co-president. “Our parents started this company by planting seeds of health and empowerment, and we’ll continue planting those seeds for years to come.”

To mark the anniversary and Earth Day, the chain will offer free plant-at-home vegetable-seed packets to the first 50 paying customers at each of its stores; a free reusable bag to every paying customer while supplies last; and a free special-edition copy of “Cows Save the Planet” to the first 60 customers who spend $60 or more.

Natural Grocers also said it will plant 30 trees in three Colorado communities “with significant or historic meaning to the company”: Golden, where the company was founded; Lakewood, where it is based; and Denver, the metropolitan community to which it has longtime ties.